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The ammonium content of granites in the English Lake District

Published online by Cambridge University Press:  01 May 2009

D. C. Cooper  and
A. D. Bradley
D. C. Cooper
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.
A. D. Bradley
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K.
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Abstract

Granitic rocks from all the exposed components of the Lake District batholith have been analysed for ammonium to look for evidence of an ammonium-rich sedimentaryprotolith. The results indicate that the ammonium content of Lake District granites is related to the type and degree of alteration experienced by the rocks. Fresh, little-altered granites from all parts of the batholith have low ammonium contents (< 30 ppm), whereas highly altered rocks contain up to 250 ppm ammonium. The most ammonium-rich rocks are highly altered specimens of Skiddaw Granite containing appreciable secondary muscovite, sericite and clay. The degree of ammonium enrichment is related to the style of alteration and host-rock lithology. Evidence for the source of ammonium is provided by strong depletion (< × 0.3) of ammonium in silty mudstones within the cordierite andgarnet hornfels zones of the Skiddaw Granite aureole. In view of the low ammonium content of some sediments and the losses known to accompany high-grade metamorphism and associated dehydration, the low primary ammonium contents of the granites are not considered to be evidence either for or against a sedimentary protolith.

Type
Articles
Information
Geological Magazine , Volume 127 , Issue 6 , November 1990 , pp. 579 - 586
Copyright
Copyright © Cambridge University Press 1990

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References

Appleton, J. D., Ridgway, J., Claros, J., Gomez Caballero, A., Rodriguez, W. & Villasenor, M. G. 1988. Lithogeochemical exploration for silver mineralisation in Bolivia, Mexico and Peru. In Silver-exploration, Mining and Treatment: Papers Presented at the International Conference held in Mexico City 21–24 November 1988, pp. 57–62. London: Institute of Mining and Metallurgy.Google Scholar
Baur, W. H. 1972. Nitrogen: crystal chemistry. In Handbook of Geochemistry, Volume 2 (ed. Wedepohl, K. H.), pp. 7/A/1–7/A/6. Berlin: Springer-Verlag.Google Scholar
Beer, K. E., Ball, T. K. & Fortey, N. J. 1985. Geochemical Recognition of Hidden Granites and Associated Tungsten Mineralisation. Report to the Commission of the European Communities Research and Development Programme Contract MSM-096-UK. Brussels: Commission of the European Community.Google Scholar
Caunt, S. 1984. Geochemical aspects of the Threlkeld microgranite, Cumbria. Transactions of the Leeds Geological Association 10, 89–100.Google Scholar
Compston, W., McDougall, I. & Wyborn, D. 1982. Possible two-stage 87Sr evolution in the Stockdale rhyolite. Earthand Planetary Science Letters 61, 297–302.CrossRefGoogle Scholar
Eugster, H. P. 1972. Ammonia, in minerals and early atmosphere. In The Encyclopaedia of Geochemistry and Environmental Sciences, vol.ivA (ed. Fairbridge, R. W.), pp. 29–33. New York: VanNostrand Reinhold.Google Scholar
Evans, J. 1989. Resetting of the Rb–Sr whole-rock isotope system of an Ordovician microgranite during Devonian low-grade metamorphism. Geological Magazine 126, 675–9.CrossRefGoogle Scholar
Firman, R. J. 1979. Intrusions. In The Geology of the Lake District (ed. Moseley, F.), pp. 146–63. Yorkshire Geological Society, Occasional Publication 3.Google Scholar
Firman, R. J. & Lee, M. K. 1986. The age and structure of the concealed England Lake District batholith and its probable influence on subsequent sedimentation, tectonics and mineralisation. In Geology in the Real World – the Kingsley Dunham volume (eds Nesbitt, R. W. and Nichol, I.), pp. 117–27. London: Institution of Mining and Metallurgy.Google Scholar
Hall, A. 1987. The ammonium content of Caledonian granites. Journal of the Geological Society of London 144, 671–4.Google Scholar
Hall, A. 1988 a. Crustal contamination of minette magmas: evidence from their ammonium contents. Neues Jahrbuchfür Mineralogie Monatshefte 3, 137–43.Google Scholar
Hall, A. 1988 b. The distribution of ammonium in granites from south-west England. Journal of the Geological Society of London 145, 37–41.CrossRefGoogle Scholar
Hallam, M. & Eugster, H. P. 1976. Ammonium silicate stability relations. Contributions to Mineralogy and Petrology 57, 227–44.CrossRefGoogle Scholar
Halliday, A. N. 1984. Coupled Sm–Nd and U–Pb systematics in late Caledonian granites and basement under northern Britain. Nature 307, 229–33.CrossRefGoogle Scholar
Harmon, R. S. & Halliday, A. N. 1980. Oxygen and strontium isotope relationships in the British late Caledonian Granites. Nature 283, 21–5.CrossRefGoogle Scholar
Honma, H. & Itihara, Y. 1981. Distribution of ammonium in minerals of metamorphic and granitic rocks. Geochimica el Cosmochimica Acta 45, 983–8.Google Scholar
Kydd, R. A. & Levinson, A. A. 1986. Ammonium halos inlithogeochemical exploration for gold at the Horse Canyon carbonate-hosted deposit, Nevada, U.S.A.: use and limitations. Applied Geochemistry 1, 407–17.CrossRefGoogle Scholar
Lee, M. K. 1984. Analysis of geophysical logs from the Shap, Skiddaw, Cairngorm, Ballater, Mount Battock and Bennachie heat flow boreholes. British Geological Survey, Geothermal Resources Programme Report 3.Google Scholar
Lee, M. K. 1986. A new gravity survey of the Lake District and three-dimensional model of the granite batholith. Journal of the Geological Society of London 143, 425–35.Google Scholar
Levinson, A. A. & Day, J.J. 1968. Low temperature hydrothermal synthesis of montmorillonite, ammonium-micas and ammonium-zeolites. Earth and Planetary Science Letters 5, 52–4CrossRefGoogle Scholar
Milovskiy, A. V. & Volynets, V. F. 1966. Nitrogen in metamorphic rocks. Geochemistry International 3, 752–8.Google Scholar
Moseley, F. 1979. The Geology of the Lake District. Yorkshire Geological Society, Occasional Publication 3.Google Scholar
O'Brien, C., Plant, J. A., Simpson, P. R. & Tarney, J. 1985. The geochemistry and petrogenesis of the granites of the English Lake District. Journal of the Geological Society of London 142, 1139–57.CrossRefGoogle Scholar
Roberts, D. E. 1983. Metasomatism and the formation of greisen in Grainsgill, Cumbria, England. Geological Journal 18, 43–52.Google Scholar
Rundle, C. C. 1979. Ordovician intrusions in the English Lake District. Journal of the Geological Society of London 136, 29–38.CrossRefGoogle Scholar
Rundle, C. C. 1981. The significance of isotopic dates from the English Lake District for the Ordovician-Silurian time-scale. Journal of the Geological Society of London 138, 569–72.Google Scholar
Shepherd, T. J., Beckinsale, R. D., Rundle, C. C. & Durham, J. 1976. Genesis of Carrock Fell tungsten deposits Cumbria; fluidinclusion and isotopic study. Transactions of the Institution of Mining and Metallurgy 13, B63–73.Google Scholar
Thompson, M. & Howarth, R. J. 1976. Duplicate analysis in geochemical practice. Analyst 101, 690–709.CrossRefGoogle Scholar
Urano, H. 1971. Geochemical and petrological study of the originsof metamorphic rocks and granitic rocks by determination of fixed ammoniacal nitrogen. Journal of Earth Sciences, Nagoya University 19, 1–24.Google Scholar
Vickers, B. P., Peachey, D. & Roberts, J. L. 1986. An investigation into the determination of ammonium in rocks. British Geological Survey, Analytical Chemistry Report 86/6.Google Scholar
Volynets, V. F. & Sushchevskaya, T. M. 1966. Nitrogenin hydrothermal processes (ammonium in inclusion solutions). Geochemistry International 9, 42–6.Google Scholar
Von Damm, K. L., Edmond, J. M., Measures, C. I. & Grant, B. 1985. Chemistry of submarine hydrothermal solutions at Guaymas Basin, Gulf of California. Geochimica el Cosmochimica Acta 49, 2221–37.Google Scholar
Wadge, A. J., Gale, N. H., Beckinsale, R. D. & Rundle, C. C. 1978. A Rb–Sr isochron age for the Shap Granite. Proceedings of the Yorkshire Geological Society 42, 297–305.Google Scholar
Webb, P. C. & Brown, G. C. 1984. Lake District Granites: Heat Production and Related Geochemistry. British Geological Survey, Geothermal Resources Programme Report 5.Google Scholar
Williams, L. B., Zantop, H. & Reynolds, R. C. 1987. Ammonium silicates associated with sedimentary exhalative ore deposits: a geochemical exploration tool. Journal of Geochemical Exploration 27, 125–41.CrossRefGoogle Scholar
Wlotzka, F. 1972. Nitrogen. In Handbook of Geochemistry, Volume 2 (ed. Wedepohl, K. H.), pp. 7/B/1–7/0/3. Berlin: Springer-Verlag.Google Scholar
Young, B., Ansari, S. M. & Firman, R. J. 1988. Field relationships, mineralogy and chemistry of the greisens and related rocks associated with the Eskdale granite. Cumbria. Proceedings of the Yorkshire GeologicalSociety 47, 109–23.Google Scholar